Promoting Freedom for Creative Architecture
Hemp rebar is a type of composite reinforcing material made up of hemp fibers combined with resin or bioplastic to form bars that can safely replace steel rebar in concrete construction. This research is being done at Rensselaer Polytechnic Institute in the US as part of their new institute for Energy, Built Environment and Smart Systems (EBESS).
Hem-based rebar has the potential to reduce corrosion problems and lower carbon emissions. Additionally, it could extend the life of a building's infrastructure by avoiding maintenance or replacement expenses, making it cheaper than steel rebar.
To fabricate hemp rebar, a team of researchers used production technology similar to 3D printing. They extracted hemp fibers wrapped in thermoplastic and spun them into rope-like coils before heating and consolidating the filament into hardened bars using a machine.
Hemp rebar is then formed using a CNC machine that reads digital files to bend and cut it into desired shapes. Their vision is to develop an automated machine that can be placed at any construction site and make hemp rebar on demand, saving time in the process.
Preliminary tests have demonstrated that hemp-based rebar is as strong as glass fiber on a weight basis, and can be used in numerous applications. Furthermore, since this rebar is made from renewable resources and contains lower embodied energy than traditional polymer rebar, it's more environmentally friendly too.
Hemp rebar can be produced from hemp plants bred for high-strength fiber, as well as from the plant's hurd. This part is the source of hempcrete - a fireproof, carbon-negative and energy-efficient building product being used worldwide in construction projects.
Rebars are essential elements in cement buildings to provide structural strength that concrete lacks. These rebars then serve to reinforce walls, floors, and ceilings of these structures.
At present, there are several alternatives to steel that are less costly and more sustainable than steel rebar, such as wood or bamboo. However, these materials still have limitations in terms of cost, durability, and availability. A team of researchers at RPI hopes their hemp-based rebar can be more cost effective than other options while they work to develop a machine which will forge the rebar on demand.
Hemp rebar is an attractive alternative to steel, being more durable and moisture-resistant than other options. This makes it the perfect choice for buildings exposed to heavy rainfall or snowfall since it won't get damaged by water damage.
Hemp-based rebar is an integral component of sustainable, low-carbon buildings that reduce global greenhouse gas emissions. Hemp plants capture atmospheric carbon twice as effectively as trees do, making them a "carbon negative" biomaterial. Furthermore, they can be rapidly and inexpensively cultivated - making them an ideal replacement for steel rebar.
